It is a common experience that when charging a battery, the battery charger integrated circuit (IC) that generates the charging current tends to overheat. The rise in temperature is caused by the IC power consumption in form of heat dissipation of the charging current. Naturally, when the charging current is reduced, the heat is also reduced. Over the years, there have been many attempts to achieve an optimal charging current value that effectively charges the battery and does not overheat battery charger IC at the same time. Some of these attempts seem to be either too complicated or too expensive. Because most of the rechargeable batteries are used in consumer electronic products, the cost and the size of the battery charger IC are important factors for the electronics manufacturers.
The present invention provides an effective, small-sized, and inexpensive circuit and a method to achieve both effective charging and overheating prevention.